The present invention relates to a hydraulic control system for an automatic transmission.
Automatic transmissions undergo a shift between two remote forward speed ratios in addition to a shift between two next adjacent forward speed ratios. Taking a four speed automatic transmission as an example, there takes place a shift between the fourth and first speed ratios, a shift between the fourth and second speed ratios, and a shift between the first and third speed ratios in addition to normal shifts between the next adjacent two forward speed ratios. If it is desired to alleviate shock occurring during each shift while preventing racing of an engine associated with the automatic transmission, many timing valves have to be provided, each for one of the above listed shifts. If this measure is employed, a bulky and expensive hydraulic control system results which is not acceptable.